Optimizing the Analysis of Volatile Organic Compounds

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Conclusion
Analyses of volatile organic compounds – VOCs – generally require concentration of the
sample using dynamic headspace (purge and trap), which reduces matrix effects and
increases sensitivity, relative to other extraction techniques. The concentrated sample is
transferred to the capillary GC column. Because GC detectors operate well with higher
flows (10mL/min.), wide-bore columns, 0.45mm ID to 0.53mm ID, are appropriate. GC/MS
instruments have the greatest sensitivity, but flow into the MS source cannot exceed
1mL/min. This makes narrow-bore columns, usually 0.18mm ID to 0.25mm ID, but up to
0.32mm ID, the preferred choice for GC/MS analysis. The column is plumbed through the
injection port to allow high desorb flows (>10mL/min.) and sample splitting at the injection
port (>10:1). Determining the type of stationary phase in the capillary column is a matter of
preference and requires an examination of conditions specific to the analysis to be performed.
Information in this guide explains many of the factors to be considered in analyses of VOCs,
but cannot anticipate every situation. If you have any questions regarding this guide, or your
particular application, please contact our Technical Service Team via email at
support@restekcorp.com or via phone at 800-356-1688 or 814-353-1300, ext. 4.
Recommended Products
Columns
Rtx ® -502.2 Columns...............................................................................................................61
Rtx ® -Volatiles Columns..........................................................................................................61
Rtx ® -624 Columns..................................................................................................................61
Rtx ® -VMS Columns...............................................................................................................61
Rtx ® -VGC Columns ...............................................................................................................62
Rtx ® -VRX Columns ...............................................................................................................62
Rtx ® -1 Columns......................................................................................................................62
Guard Columns & Transfer Lines ...................................................................................62, 63
Accessories
Connectors .......................................................................................................................20, 64
Direct Injection Liner, Vu-Tight ® ...........................................................................................18
ELCD Reaction Tubes ...........................................................................................................29
ELCD Transfer Lines.............................................................................................................27
FID Jets ..................................................................................................................................25
Gas Leak Detector ...........................................................................................................36, 65
Gas Pressure Regulator ..........................................................................................................28
Inlet Liners for Volatiles Analysis..........................................................................................65
Low-Volume Injectors......................................................................................................19, 63
Moisture Control Bypass Line...............................................................................................14
MSD Source Nut....................................................................................................................35
PID Lamps .............................................................................................................................24
Sample Vials...........................................................................................................................65
Spargers, Purge and Trap .........................................................................................................9
Syringes for Purge and Trap ..................................................................................................64
Analytical Reference Materials
502.2 Mixes & Kits................................................................................................................68
601 & 602 Mixes & Kits .......................................................................................................68
624 Mixes & Kits.............................................................................................................67, 68
8260 Mixes & Kits...........................................................................................................66, 67
CLP VOC Mixes & Kits...................................................................................................68-70
PVOC/GRO/BTEX Mixes .....................................................................................................67
Note: Many additional reference materials, including custom mixes, are available from
Restek. Please call us at 800-356-1688, or contact your Restek distributor; we’ll help you
find what you’re looking for.